The present invention relates to a writing instrument which is meant in a broad sense and in which a plurality of cartridges are fitted and coupled in series with each other in the longitudinal direction thereof so that the cartridges are removable from each other.
A conventional writing instrument of such kind was disclosed in the Japanese Utility Model Publication No. 14633/85. In the writing instrument, a plurality of cartridges having cores at the tips of the cartridges are fitted and coupled with each other in the longitudinal direction thereof removably from each other and then housed in an outer cylinder of relatively large length. The core of the foremost cartridge is protruded from the tip of the outer cylinder to write a character or the like by the core. When the core of the foremost cartridge is worn out due to the writing, the cartridge is pulled out of the outer cylinder from the tip thereof and inserted into the outer cylinder from the butt thereof so that the second foremost cartridge in the outer cylinder is moved to the tip thereof by being pushed and the core of the cartridge is protruded from the tip of the outer cylinder in order to be used for writing. Since the plural cartridges are sequentially moved by being pushed, to continually use the writing instrument, the instrument cannot be used even if only one of the cartridges is lost. This is a problem. Since the holding pressure on the writing instrument at the time of writing cannot be withstood only by the cartridges coupled in series with each other, the instrument cannot be used without the outer cylinder. Therefore, the outer cylinder is needed. This is another problem. Besides, the cartridges whose cores are worn out due to writing can be discarded but cannot be utilized for other uses such as being used as building blocks for toying. This is yet another problem.